local voucherId = ARGV[1]
local userId = ARGV[2]
local orderId = ARGV[3]
local stockKey='seckill:stock:' .. voucherId
local orderKey='seckill:order:' .. voucherId

if(tonumber(redis.call('get',stockKey)) <=0 ) then
    return 1
end

if (redis.call('sismember',orderKey,userId) ==1 ) then
    return 2
end

redis.call('incrby',stockKey,-1)
redis.call('sadd',orderKey,userId)
redis.call("xadd","stream.orders","*","userId",userId,"voucherId",voucherId,"id",orderId)
return 0